User information is collected and used by almost every website and Internet enterprise. User information is also shared between enterprises, mostly through bilateral agreements in which users whose information is being shared play no part. Thus, one commercial entity may sell its historical customer usage data to another entity. Some enterprises even use selling of customer profiles and data as their primary business model. Several Internet companies are racing to build computer programs and devices that contain (embedded) computer programs such as digital assistants and robots. Several enterprises have suffered user data breaches and such incidents seem to be increasing in number and ferocity of attacks. Thus, a data sharing mechanism that is both efficient and preserves user privacy will be of significant social and commercial benefit.